But then again, That brings up the statement of different masks, I collect gas-masks and some I can completely see through no problem, Some are like putting your head in a cardboard and poking 2 holes in it with a pin.

The GP-5 as a starter is a good one as it is slightly intrusive of your view, But not to the extent of not being able to see properly.

The only problem with the SHoC version is that it was pretty primitive (Though SHoC isn't the most modifiable STALKER game out of the trilogy) when it came to using it and the effects of it, But then again, It was a minimod. But with CoP a system could be set-up so we can upgrade them, NPCs wear them and have a proper filter system.

The idea would be that you would have gas-masks with expirable filters, Like to this mod that is now abandoned: Moddb.com

Different gas-masks could be cheaper and have different filters, For instance.

A cheap GP-5 (Probably what you would start with and what rookie STALKERS would have) would use the standard filters dirt cheap filters for it that would last about 8 hours (Or the in-game version) before needing to be replaced with fairly good resistance, Though it still wouldn't survive a long time in a high-radiation area for much longer due to the low resistance. But you could upgrade it to use 40mm NATO filters that last about 20 hours for quite a high price.

Or you could possibly get an imported M40 mask from the US for a higher cost, But would have better resistance than the GP-5 (This is the kind of thing mercs would use, As they are already on the merc suits). The filters would be C2A1 filters that would last about 14 hours before needing to be replaced, More costly than the standard GP-5 filters and the longer-lasting NATO filters, But would have better resistance.